CoMP (Coordinated multiple point) is one of the important techniques for the LTE-Advanced (Long Term Evolution-Advanced) system to expand the network edge coverage and ensure communications of edge users. The CoMP may be divided into downlink transmitting CoMP and uplink receiving CoMP. One type of the downlink transmitting CoMP is: when communicating with a terminal, a plurality of cells transmits downlink signals to the terminal simultaneously, thereby ensuring the quality of downlink signals received by the terminal.
The existing CoMP scenario may be divided into intra-eNB (intra-evolved NodeB) and inter-eNB (inter-evolved NodeB). The intra-eNB scenario is that: a plurality of cells transmits data to a terminal simultaneously where the plurality of cells belongs to one base station. Therefore, time difference or phase difference of arrival of downlink signals from the plurality of cells at the terminal can be controlled within a relative low range. The inter-eNB scenario is that: a plurality of cells transmits data to a terminal simultaneously, where the plurality of cells does not belong to one base station. Therefore, time difference or phase difference of arrival of downlink signals from the plurality of cells at the terminal is relative difficult to be controlled within a relative low range.
In order to solve the problem that, in the inter-eNB scenario, it is difficult to control time difference or phase difference of arrival between downlink signals from the plurality of cells at the terminal to be within a relative low range, the time difference or phase difference may be reduced. For example, the following take a scenario that two cells send data to a terminal simultaneously in the inter-eNB scenario as an example, where one of the two cells is a serving cell, and the other is a coordinated cell. The terminal respectively calculates time difference of sending downlink data between two cells according to CSI-RS (Channel State Information-Reference Signal) sent by the two cells; the terminal obtains information about time difference or information about phase difference between the two cells according to the time differences; the terminal sends the information about time difference or information about phase difference to the serving cell, and the serving cell shares the information about time difference or information about phase difference with the coordinated cell; the coordinated cell adjusts the sending time, phase, or pre-coding manner of transmitted signals according to the information about time difference or the information about phase difference.